[Wasm] Add box and stdlib tests in wasi mode

libraries/stdlib/wasm/js/test/unsafe/MemoryAllocationJsTest.kt

@@ -0,0 +1,18 @@
+package test.wasm.unsafe
+
+import kotlin.wasm.unsafe.*
+import kotlin.test.*
+
+private fun jsConcatStrings(a: String, b: String): String =
+    js("a + b")
+
+@OptIn(UnsafeWasmMemoryApi::class)
+class MemoryAllocationJsTest {
+    @Test
+    fun testJsIntropInsideAllocations() {
+        withScopedMemoryAllocator { allocator ->
+            assertEquals(jsConcatStrings("str1", "str2"), "str1str2")
+            allocator.allocate(10)
+        }
+    }
+}